如果一张表是列式存储的，比如：
CREATE TABLE "DB2TST "."T0417" (
"ID" INTEGER )
IN "TBS2"
ORGANIZE BY COLUMN;
那么删除完数据之后的腾出来的空间是无法被新插入的数据使用的，表只会越来越大。并且无法按照普通表的方式去reorg表,会报错SQL1667N：
db2 reorg table t0417
SQL1667N The operation failed because the operation is not supported with the
type of the specified table. Specified table: "T0417". Table type: "ORGANIZE
BY COLUMN". Operation: "REORG TABLE". SQLSTATE=42858
信息中心的页面 Space reclamation for column-organized tables 中有明确说明，列式存储的表删除数据以后的空间不能被复用
When a row in a column-organized table is deleted, the row is logically (but not physically) deleted. As a result, the space that is used by the deleted row is not available to subsequent transactions, and remains unusable until space reclamation occurs. For example, consider the case where a table is created and 1 million rows are inserted in batch operation A. The size of the table on disk after batch operation A is 5 MB. After some time, batch operation B inserts another 1 million rows. Now the table consumes 10 MB on disk. At this point, all of the rows that were inserted in batch operation A are deleted, and the table size on disk remains 10 MB. If a third batch operation C inserts another 1 million rows into the table, 5 MB of additional space is required. (With row-organized tables, the rows that are inserted in batch operation C would use the space that was vacated by the deleted rows from batch operation A.) A REORG TABLE command is required to reclaim the space that was used by the rows inserted in batch operation A.
因此，删除完数据之后，要想回收空间，必须做reorg操作，而且要带有RECLAIM EXTENTS参数：
db2 reorg table tablename RECLAIM EXTENTS ALLOW WRITE ACCESS